Insolation: Incoming solar radiation in short waveform. It is the rate of delivery of direct solar radiation per unit of a horizontal surface; broadly: that relating to total solar radiation. It is the occurrence solar radiation onto some object. Particularly, it is a measure of the solar energy that is incident in a particular region over a set phase of time. Usually, it is expressed in kilowatt-hours per square meter per day.
Not all of the solar energy that reaches the Earth actually reaches the surface of the Earth. Although 1367 W/m2 of daylight strikes the external atmosphere, about 30% of it is reflected back into space. After this reflection, an assured spot on the Earth might see nearly all or almost none of this sunlight. There are many aspects that help find out how much sunlight actually reaches a given region, but some of them contain sun position, air accumulation, day duration, cloud exposure, and toxic waste levels.
Insolation Weathering is a kind of physical weathering which engages repeated heating and cooling of rock over daily cycles, increasingly breaking apart the grains of rock.